Compact compressor unit

ABSTRACT

A refrigeration compressor unit comprising a compressor, a motor and an oil separating system, wherein the compressor is mounted within the oil separator housing, and the motor is mounted on the compressor.

United States Patent Lundberg et a1.

1451 July 23, 1974 COMPACT COMPRESSOR UNIT Inventors: Anders Lundberg; Rolf Axelsson,

both of Norrkoping, Sweden Stal Refrigeration AB, Vasteras, Sweden Filed: Dec. 18, 1972 Appl. No.: 316,291

Assignee:

130] Foreign Application Priority Data Dec. 23, 1971 Sweden 16587/71 US. Cl 417/321, 418/77, 55/438, 62/473 Int. Cl. 801d 45/00, F25b 43/02, FOlc 21/04 Field of Search 418/97, 98, 99, 100; 417/321; 55/438; 62/469, 473; 415/168 [56] References Cited UNITED STATES PATENTS 2,152,056 3/1939 Kenney et a1 418/98 X FOREIGN PATENTS OR APPLICATIONS 147,656 11/1936 Austria 418/100 872,110 7/1961 Great Britain 418/99 Primary Examiner-Carlton R. Croyle Assistant Examiner-Richard E. Gluck 5 7] ABSTRACT A refrigeration compressor unit comprising a compressor, a motor and an oil separating system, wherein the compressor is mounted within the oil separator housing, and the motor is mounted on the compressor.

4 Claims, 1 Drawing Figure PATENTEU JUL 2 31974 1 COMPACT COMPRESSOR UNIT BACKGROUND OF THE INVENTION In compressor units used for refrigeration plants, compressor, motor and oil separator are normally mounted separately, often on a common chassis. Because the requirements for efficient oil separation, discussed below, dictate large dimensions for the oil separating system, the separate mounting of compressor and motor make the resultant unit quite bulky.

Oil separating systems for refrigeration compressors, where refrigerant and lubrication oil may be thoroughly mixed, are subject to heavy demands to prevent the oil from being transported by the refrigerant into the refrigeration plant. These demands create considerable space requirements, both to accomodate various separation devices such as baffles, filter separators and the like, and also to provide large cross sections, and hence low speeds, for the flow of refrigerant oil, thus allowing time for the oil to separate out.

It is clear, therefore, that the large volume necessary for the oil separating system, aggravated by the separate mounting of compressor and motor, render the conventional refrigeration compressor unit awkwardly large and space-consuming.

SUMMARY OF THE INVENTION The present invention utilizes a small part of the large volume of the oil separating system, placing the compressor inside the oil separator housing.

lt might be expected that the insertion of the compressor into the oil separator would require making the oil separator housing even larger, but this is not so. Because the oil separator must already have sufficient volume to provide low flow speeds, allowing the oil time to settle, the introduction of the compressor, which oecupies small space relative to the dimensions of the oil separator housing, does not interfere.

In addition, by mounting the motor on the compressor, this invention provides a compact unit far easier to handle than those of the prior art.

The combining of compressor and oil separating system as disclosed herein creates advantages in compressor lubrication over previous constructions, and these will be indicated in the following description, which, together with the accompanying drawing, will make clear the principles and features of the invention.

DRAWINGS The accompanying drawing shows an elevational view, partly in section, of a preferred embodiment of a compressor unit constructed according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENT The drawing shows a motor 1 for driving compressor 2, which may be, for example, a screw compressor, through shaft-coupling 14. Compressor 2 is positioned inside oil separator housing 3. The outlet port 19 at the bottom of compressor 2 opens into a primary separator 4 for rough separation of the oil. As shown, this separator 4 comprises a horizontal base plate for slowing down the exhaust from compressor 2 and a basket of coarse metal cloth or the like attached between the plate and the compressor outlet. Primary separator 4 functions as follows: as the mixture of compressed refrigerant and oil emerges from compressor 2 oil particles are intercepted and detained by the base plate and the wires of the metal cloth, while the gaseous refrigerant passes in a diffuse flow.

Upper portion 10 of oil separator housing 3 functions as the top portion of a compressor 2 as well, and is provided with inlet port 8 and outlet port 9 for passage of the refrigerant from and to the compressor 2. Motor I is attached through flanges to top portion 10 by means of cylindrical support member 16.

In order to provide a sufficiently low flow rate in separator housing 3 for the mixture of gaseous refrigerant and oil so that oil drops have time to sink to the bottom of housing 3 and to be collected there in sump 6, housing 3 must have a rather large diameter and large volume. This provides adequate room for compressor 2, the volume of which is only a fraction of that of separator housing 3. For improved oil separation, secondary oil separators in the form of filter domes S are mounted on diaphragm 17 in the upper part of housing 3 between compressor 2 and the outer wall of housing 3.

The arrangement of compressor 2 and housing 3 in vertical position is most convenient for the mounting of secondary oil separators 5 as shown. The invention is not, however, restricted to the vertical arrangement of compressor 2 and housing 3, since both could be positioned with horizontal axes, (not shown). In this case, compressor 2 could also be placed in the upper part of housing 3, oil sump 6 in its lower part, and secondary separators 5 mounted on horizontal diaphragm 17 in housing 3. In either vertical or horizontal orientation, the essential feature is to provide flow paths for the gasoil mixture so that sufficiently slow flow rates, and, therefore, adequate oil deposition, is ensured.

As previously indicated, the oil is collected in sump 6 at the bottom of housing 3, from where it can be forced upward by the gas pressure in housing 3 through tube 12 and filter 7 to intake 18 at the upper end of compressor 2. Other intakes for oil (not shown) may be provided at intermediate stage of compressor 2.

When the oil leaves compressor 2, it is hot, since the oil provides the main cooling for compressor 2 during its operation. The oil must, therefore, be cooled before being returned through tube 12 and filter 7 to compressor intake 18. This can be accomplished in a known manner, for example, as shown, by conducting cooled condensed refrigerant through tube 11 into oil sump 6, where the condensed refrigerant is vaporized and cools the oil. The vaporized refrigerant then rises into housing 3 and through secondary oil separators 5 to outlet 9. The supply of refrigerant through tube 11 may be regulated by regulating valve 13, which in turn may be controlled by, for example, temperature sensitive device 15 in oil sump 6. Alternately, instead of direct cooling, as shown, a refrigerating coil may be introduced into oil sump 6, from where the heat refrigerant, free of oil, may be fed back to the compressor, preferably at a point where the pressure level approximately equals the pressure of the vaporized refrigerant being returned.

The nature and features of this invention have been described and its scope is defined by the following claims.

What is claimed is:

l. Compressor unit for a refrigeration plant, comprising:

a compressor;

a motor for driving said compressor;

an outlet port from said compressor;

oil separating means in the form of a container for separating from each other refrigerant from the plant and oil for lubrication of said compressor;

said refrigerant and said oil leaving said outlet port together;

said compressor being arranged within said container;

a primary oil separator, surrounding and covering said outlet port;

a secondary oil separator, dividing said container into an upper part and a lower part;

an oil sump at the bottom of said lower part of said container;

said outlet port of said compressor and said primary oil separator being arranged above said oil sump and below said secondary oil separator; and

a discharge port for the entire compressor unit arranged in said upper part of said container above said secondary oil separator.

2. Compressor unit as defined in claim 1, wherein said compressor comprises a lubrication system connected to said oil sump, said oil for lubrication of said compressor being forced from said oil sump into said lubrication system by pressure, said pressure being generated within said container by said refrigerant from the plant.

3. Compressor unit according to claim 1, wherein said compressor and said oil separator housing share a common end portion, said end portion being provided with an inlet and said outlet discharge port for the compressor unit.

4. Compressor unit as defined in claim 3, wherein said motor is attached to said common end portion. 

1. Compressor unit for a refrigeration plant, comprising: a compressor; a motor for driving said compressor; an outlet port from said compressor; oil separating means in the form of a container for separating from each other refrigerant from the plant and oil for lubrication of said compressor; said refrigerant and said oil leaving said outlet port together; said compressor being arranged within said container; a primary oil separator, surrounding and covering said outlet port; a secondary oil separator, dividing said container into an upper part and a lower part; an oil sump at the bottom of said lower part Of said container; said outlet port of said compressor and said primary oil separator being arranged above said oil sump and below said secondary oil separator; and a discharge port for the entire compressor unit arranged in said upper part of said container above said secondary oil separator.
 2. Compressor unit as defined in claim 1, wherein said compressor comprises a lubrication system connected to said oil sump, said oil for lubrication of said compressor being forced from said oil sump into said lubrication system by pressure, said pressure being generated within said container by said refrigerant from the plant.
 3. Compressor unit according to claim 1, wherein said compressor and said oil separator housing share a common end portion, said end portion being provided with an inlet and said outlet discharge port for the compressor unit.
 4. Compressor unit as defined in claim 3, wherein said motor is attached to said common end portion. 